I don't think he has a day job anymore, even if that was true in the beginning. And yes, he has salaries to pay, but not that many. The main reason why it takes time is that he's doing 95% of the art himself. Some other do animations and that's it. And I understand this, his art is good and even better than in the beginning. Sure in an ideal world he could find someone as good as him who could replicate his style and help release the updates faster, but guys at this level usually already have a job paying more than what DC would offer. So yeah, out of the 60k he makes, he probably keeps around 40k for himself, if you include money for coders, posers, writers and the music guy. Good for him, he has 3 kids and he wouldn't be here if his art and story sucked.
No one's forcing his Patrons to pay. And people have been paying for way more stupid useless stuff than this. Just look at Apple. (free unrelated jab at a brand I don't like).